This competitive revision supplement proposal to P01AT005013 "Metabolic and Immunologic Effects of Meditation" is in response to NOT-OD-09-058: NIH Announces the Availability of Recovery Act Funds for Competitive Revision Applications. Immune cell aging, as measured by telomeres, the caps protecting the ends of chromosomes, and telomerase, the enzyme that lengthens telomeres, has become an important measure of biological age and predictor of early mortality. Our data and other's have shown that both obesity and stress are associated with shorter telomeres in cross-sectional and over longitudinal studies. It is thus important to assess whether reducing obesity and stress might protect telomeres. Our Center for Excellence in Research on Complementary and Alternative Medicine (CERC) is ideally poised to test how weight loss and weight loss with stress reduction might reduce aging ofthe immune system. Our CERC intervention (Craving and Lifestyle Management through Mindfulness, or CALMM) aims to decrease obesity (and particularly visceral adiposity) through reducing stress and stress-related eating, improving stress-related Cortisol patterns, and improving awareness of hunger-satiety cues. We are conducting a randomized, controlled clinical trial in which participants are assigned to one of two groups that meet weekly for 16- sessions: (1) CALMM, which integrates mindful eating and mindful meditation based stress reduction with diet and exercise;and (2) Diet-Ex, with diet and exercise alone. Detailed evaluations of perceived stress and other psychological measures, physiological responses to structured laboratory stressors, weight, Cortisol patterns, and fat distribution are obtained in the parent study. This supplement would allow us to test whether the addition of a meditation/stress reduction component to diet and exercise (CALMM) leads to improvements in telomerase activity and in telomere length over one year. We will compare changes in telomerase activity and telomere length between groups (n=100, approximately half in each group) between baseline and post-intervention (12 months). Additional analyses will test whether changes in weight, stress, mood, insulin resistance, and other measures such as Cortisol patterns predict changes in cell aging measures. The study adds measures of telomere length, telomerase activity, and examines these across cell types as well as in key subpopulations (B cells, CD4, CD8+CD28+, and CD8+CD28- cells). This study will be one ofthe first interventions to test effects of meditation and stress reduction on cell aging, and can provide further insight into stress and metabolic mechanisms of mind-body influences on cell aging.